Method of producing colored china clay images



Dec. 27, 1955 J. M. M. BACH 2,728,158

METHOD OF PRODUCING COLORED CHINA CLAY IMAGES 1 Filed April 30, 1952METHOD OF PRODUCING COLORED CHINA CLAY IMAGES Johan Martin Michel Bach,Rotterdam, Netherlands Application April 30, 1952, Serial No. 285,353Claims priority, application Netherlands May 2, 1951 7 Claims. (Cl.41-26) The invention relates to a process for the reproduction of apicture, painting or photograph on an article as a tinted relief.

It is an object of the invention to provide for a method of producingarticles, having at least at a part of the surface a decoration which isa good low relief reproduc- H tion of a picture, a painting or aphotograph having the same gradations in tint or in colour as theexample.

A further object is the method of producing articles, having at least ata part of the surface a tinted decoration in low relief, which is a goodreproduction of a picture, a painting or a photograph in an almostautomatic way.

Other objects of the invention will become apparent hereinafter in thespecification.

A sheet of gelatine or gelatinous material is photosensitized by theaction of a solution of dichromate salts in water, whereafter it isdried in the air. This sheet is pressed against a photographic negativeor diapositive of the picture that I Want to reproduce, and light ispassed through this negative or diapositive on the gelatin sheet.

The time of exposure varies in accordance with the intensity of thelight and the darkness of the picture; as a rule a time of exposure tosunlight of l-S hours is sufficient. Hereafter the sheet is soaked inwater, e. g. in water of about 30 C. for l-6 days. In the water thegelatine swells to an extent, dependent on the intensity of the light towhich it has been exposed and on the gelatin surface an exactreproduction in low relief of the picture that has to be reproduced isformed. When dried in the air this low relief picture remains on thegelatin sheet. The difference in height of the different parts of thelow relief varies with the time of exposure and the soaking time. Inorder that I may perform in the right way the tinting or coloringprocess as described hereinafter, the difference in height of theembossed parts and the recesses has to be at least mm. and preferably3-5 mm.

This gelatin sheet can be used as such as a mould but I prefer to hardenit before using it for this purpose by the action of a hardening agentas e. g. a solution of formaldehyde in water. It may be used as acasting mould for substances like gypsum, cement, concrete and othersubstances, hardening at low temperatures.

When a casting with a curved surface e. g. a spherical form is wanted, Ifix a sensitized and exposed gelatin sheet on a surface of the desiredform and soak and dry it in this state.

When castings or mouldings of substances as e. g. resins, metals orplastics are wanted, these cannot be pressed or cast in a gelatin mould.For these purposes I prepare a gelatin low relief andmake by pressing itinto casting sand a casting mould in which a metal is cast. This metalobject can be used as a mould for pressing the desired articles.

All the articles made in this or a similar way have on the surface inlow relief a good reproduction of the picture, painting or photograph,the depth ofthe recesses of this relief corresponding exactly with thegrade of tint-or colour of the example.

nite States Patent The invention consists in the method of tinting orcoloring these low relief pictures to exact reproductions of the exampleand in the articles, having tinted or colored reproductions made by thistinting or coloring process.

According to the invention this coloring process is performed bybringing into the recesses of a low relief picture on the surface alocally varying little quantity of a tinting or a coloring matter, thisquantity locally corresponding with the depth of the recesses andtherefore providing herein a grade of tint or colour corresponding withthe gradations in tint or colour of the example, providing a tinted orcolored low relief reproduction of the example.

One way of carrying out this process is by sutfusing the low reliefpicture with a thin layer of a slow settling diluted suspension of atinting or coloring agent in a suspending liquid, settling of saidtinting or coloring agent in a quantity locally varying incorrespondence with the thickness of the layer of suspension on thesurface and therefore varying also with the depth of the recesses,removing the suspending liquid after that said tinting or coloring agentis substantially settled.

To obtain good results the concentration of the tinting or coloringagents in the suspension must not be more than 6 percent by weight, andpreferably between 1 and 2 percent. When greater concentrations are usedthe gradations of the reproduction differ from the gradations of theexample.

Further the surface of the low relief has to be wetted evenly by thesuspension. When the article is of a type diflicultly moistened by thesuspending agent, as e. g. metal by water, a surface active agent, as e.g. carboxymethyl-cellulose, must be added to the suspending liquid. Whenthe article is of a porous character, as e. g. an unglazed ceramic body,this body has to be wetted with the suspending liquid before sufiusingthe suspension on it in order to prevent sucking of the suspension intothe body.

In order to control the settling time of the suspension I may add to thesuspension a protective colloid.

If it is wanted to increase the settling time I can do this also byincreasing the viscosity of the suspending liquid by addition of asubstance which increases the viscosity of this liquid, as e. g.addition of sugar, when this liquid is water. When the whole surface ofthe low relief is suffused at a time, a tinted picture is obtained.

It is, however, possible to apply the process successively withsuspensions of different dyes on different parts of the low relief forthe production of pictures in different colours.

When objects as a vase or a can or jar must be provided with tinted orcolored low relief pictures at all sides the process as described time.On sutfusing and settling of the suspension the low relief must besubstantially horizontal. Therefore from a round shaped article only alittle part of the surface can be colored at a time. In this case thetinting or coloring matter is applied as a dry powder on themoist'surface of the matrix or mould before casting or moulding thearticle. By blowing the tinting matter as a dust over the wet surface ofa mould with a low relief this dust adheres nearly only on theelevations, and no coloring matter is deposited in the recesses.

I canalso apply the coiour powder on the surface of a matrix with a lowrelief so that the quantity varies according to the height of theelevations by tapping all over the wetted surface of the low relief witha linen bag filled up with the colour powder.

If after coloring of the matrix a casting is made in this matrix, e. g.a casting of clay in a matrix of gypsum, the powder is transferred tothe surface of the casting without mixing substantially with the castingsubstance, and

hereinbefore is taking up much 3. after solidification a casting with agood tinted low relief reproduction of the example is obtained.

In the accompanying drawing:

Fig; lzis SXIOPTPIZHViGW of achina tile :withua tinted lowreliefreproduction of 'aphotograph of a boy;

Fig.2 is atransverse vertical. sectional view thereof .on line IITII ofFig. 1.

Thebody 13 isof white burnt china clay. Onthe surfaceais a .good reliefrpicture vof e. g. aboys portrait. Thedark parts of the bonnet and thesurrounding rim have deep recesses indicated with: '10, 12, 17 andlS.The hair of the .boy forrnsrecessesof lower depth indicated with 13;theparting .14 has almost the same height. as'the uncolored part of thetilelo.

.This tile .is soaked with water :and suffused with a suspension of 1percent of cobaltoxide in a percent solutionof sugar in water, byweight, so that the recesses areucompletely filled-:with it.

off. Hereafter the surface of the tile is'sprinkled Witha glaze powdermelting to a translucent glaze, and the tile is burnt. The result isindicated in Figure 1..

Agood result is also obtained when from a dried casting of Ichina clay,whichis not burnt, the low relief picture is suffused with a suspensionof .a ceramic coloring agent as cobaltoxide, manganese oxide, ferricoxide etc., and afterwards the colored casting is burnt.

The process is applicable in the-same Way onlow relief pictures of metalcastings, of chocolate, of soap, of resin, of rubber etc.

What I claim is:

1. In a process of producingcolored china clay images, the steps ofdepositing on a substantially horizontal surface of a cast china claybody anaqueous suspension of a water-insoluble metal. compound notabsorbable by said china clay body and which on burning forms a coloredcompound with china clay in an amount sufiicient to cover said surfaceof said cast body and containing a maximum of 6% byweight of said metalcompound and also conraining sugar as a viscosity increasing additive,said surface having depressions of varying depth; allowing said metalcompound in the thus applied suspension to settle in the saiddepressions in said surface of said cast body, thereby forming a coatingof said metal compound on said surface the thickness of which varies indirect proportion to the depth. of said depressions; removing thesupernatant liquid from said surface; and burning said cast china claybody thereby combining said metal compound with the china clay andforming a colored china clay image.

2. .ln a-process of producing colored china clay images, the steps ofdepositingon a substantially horizontal surface of a cast china claybody an aqueous suspension of a water-insoluble metal compound selectedfrom thegroup consisting of oxides of cobalt, manganese and iron in anamount sufficient to cover said surface of said cast body and containinga maximum of 6% by weight of said metal compound and also containingsugaras a viscosity increasing additive, said surface having depressionsof varying depth; allowing said metal compound in the thus appliedsuspension to settle in the said depressions in said surface of saidcast body, thereby forming a coating of said metal compound on saidsurface the thickness of which varies in direct proportion to the depthof said depressions; removing the supernatant liquid from said surface;and burning said vcast china clay bodythereby combining said metalcompound with the china clay and forming a colored china cl ay image.

in a process of producing colored china clay images, the steps ofdepositing on a substantially horizontal surface of a cast china claybody an aqueous suspension of cobalt oxide which is not absorbable bysaid china clay body and which on burning forms a colored compound withchinaelay in an amount sufficient to cover said sur faeciof said castbody containing a maximum of 6% by weight of saidicobal-t oxide and alsocontainingsugar After .some minutes the. CObflltOXidCzlS .settleddown,and :the sugarsolution poured.

as a viscosityincreasing additive, said surface having v.depressions ofvarying depth; allowing said cobalt oxide in the thus appliedsuspension" to settle in the said depressions in said surface of saidcast body, thereby forming a coating of said cobalt oxide on saidsurface the thickness of which varies in direct proportion to the depthof said depressions; removing the supernatant liquid from said surface;and burning said castchina clay body thereby combining said cobalt oxidewith the china clay and forming a colored china clay image.

4. in a process of producing colored china clay images, the steps ofdepositing on a substantially horizontal surface of a cast china claybody an aqueous suspension of a water-insoluble metal compound selectedfrom the group consisting of oxides of cobalt, manganese and iron andcontaining a surface active agent in an amount suflicient to cover saidsurface of said cast body and containing a maximum of 6% by'weight ofsaid metal compound'and also "containing sugar as -a"viscosityincreasing additive,"

said surface having depressions of varying depth; allowing said metalcompound in the thus applied suspension to settle'inthe said depressionsin said "surface of said cast body,thereby'forming a coatingof saidmetal compound on'said surface the thickness of which varies in directproportionto the depthof'sa'id depressions; removing-the supernatantliquid from said 'surface; and burning said cast china'clay'body'thereby combining said metal compound with the china clay andforming acolored china clay'ima'ge.

5. Ina process of producing'co'lored china clay images, the steps ofdepositing on a"subst'antially horizontal surface of a cast chinacl'ay'body an aqueous suspension of a water-insoluble metal compoundselected'fromthe group consisting of cobalt, manganese'and iron in anamount sufiicient to cover said surface of said cast body and con:taining 21 maximum of 6% by weight of said metal compound and alsocontaining sugar as a viscosity increasing additive,'said surface havingdepressions of varying depth; allowing said metal compound in 'the thusapplied suspension to settle in the-said depressions in said surface ofsaid cast body, thereby forming a coating of said metal compound on saidsurface the thickness of which varies in direct proportion to the depthof said depressions; removing the supernatant liquid froth-said surface;and burning said cast china clay thereby combining said metal compoundwith the china clay and forming a colcred china clay image.

6. In a process of producing colored china clay images, the steps(if-wetting the surface of a cast china clay body with water; depositingon 'a substantially horizontal surface of 'th'e'thus wetted -surface ofsaid cast china clay body'an aqueous suspension of a water-insolublemetal compound not 'absorbable by said china clay body and which on'burningforms a colored compound with china clay in an amount sullicientto' cover said surface of said cast body and containing'a maximum of 6%by weight of said metal compound and also containing sugar as aviscosity increasing'addi tive; said surface having depressions ofvarying depth; allowing said metal compound in thethus'appliedsuspensionto settle-in the said depressions in said surface"of 'said'cast body, thereby forming a coating of said metal compound onsaid surface the thickness of which varies in direct proportiontothedepth of said depressions; removingthesupernatant liquid from saidsurface; and burningsaid cast china clay body thereby combining saidmetal compound with the china clay and forming a-:colored china clayimage.

7. In a-process of producing colored china clay images, the stepscfwettingthe surface 'of a cast china claybody with water; depositing ona substantially horizontal surface or" the thuswetted surface of-saideast china clay body an aqueous --suspension of-a water insoluble metalcompound selected from the group consisting of oxides of cobalt.manganese andiiron inl an amount sufiicient to cover said surface ofsaid cast body-'andcontaining amaximum of 6% by weight of said metalcompound and also containing sugar as a viscosity increasing additive,said surface having depressions of varying depth; allowing said metalcompound in the thus applied suspension to settle in the saiddepressions in said surface of said cast body, thereby forming a coatingof said metal compound on said surface the thickness of which varies indirect proportion to the depth of said depressions; removing thesupernatant liquid from said surface; and burning said cast china claybody thereby combining said metal compound with the china clay andforming a colored china clay image.

References Cited in the file of this patent UNITED STATES PATENTS

1. IN A PROCESS OF PRODUCING COLORED CHINA CLAY IMAGES, THE STEPS OFDEPOSITING ON A SUBSTANTIALLY HORIZONTAL SURFACE OF A CAST CHINA CLAYBODY AN AQUEOUS SUSPENSION OF A WATER-INSOLUBLE METAL COMPOUND NOTABSORBABLE BY SAID CHINA CLAY BODY AND WHICH ON BURNING FORMS A COLOREDCOMPOUND WITH CHINA CLAY IN AN AMOUNT SUFFICIENT TO COVER SAID SURFACEOF SAID CAST BODY AND CONTAINING A MAXIMUM OF 6% BY WEIGHT OF SAID METALCOMPOUND AND ALSO CONTAINING SUGAR AS A VISCOSITY INCREASING ADDITIVE,SAID SURFACE HAVING DEPRESSIONS OF VARYING DEPTH; ALLOWING SAID METALCOMPOUND IN THE THUS APPLIED SUSPENSION TO SETTLE IN THE SAIDDEPRESSIONS IN SAID SURFACE OF SAID CAST BODY, THEREBY FORMING A COATINGOF SAID METAL COMPOUND ON SAID SURFACE THE THICKNESS OF WHICH VARIES INDIRECT PROPORTION TO THE DEPTH OF SAID DEPRESSIONS; REMOVING THESUPERNATANT LIQUID FROM SAID SURFACE; AND BURNING SAID CAST CHINA CLAYBODY THEREBY COMBINING SAID METAL COMPOUND WITH THE CHINA CLAY ANDFORMING A COLORED CHINA CLAY IMAGE.